I've been using TopStyle Pro as an HTML editor, and it ties in nicely with CSS. One thing I miss with WeBuilder, is when you type <DIV class=" it doesn't popup with available CSS styles. Its not until you close the tag, and put the cursor in the quotes that the code inspector window opens, where you can select a CSS style.
If it can't autocomplete, (preferably as soon as you type the first double quote) then it would be nice if double clicking the 'class' text in the Inspector window should toggle through the available CSS styles.